Method: Data of patients with a diagnosis of neuroleptic malignant syndrome between July and December in each of the 5 years from 2004 to 2008 were extracted from the Japanese Diagnosis Procedure Combination database. Data included patient background, use of antipsychotics, and in-hospital mortality. Propensity score matching was performed to formulate a balanced 1:1 matched study and to compare in-hospital mortality between neuroleptic malignant syndrome patients taking typical antipsychotics and those taking atypical antipsychotics.

Conclusions: The results show that neuroleptic malignant syndrome remains a life threatening disease among patients receiving antipsychotics. A tendency for lower mortality in the atypical antipsychotic group may reflect differences in the pathophysiology. However, to clarify whether there is a difference in neuroleptic malignant syndrome–related mortality with the 2 types of antipsychotics, further studies with larger samples are needed.